FAIR VALUE MEASUREMENTS (Tables)

12 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Fair Value Hierarchy of Financial Assets and Liabilities

The following table represents the Company's fair value hierarchy for its financial assets and liabilities:

Fair Values as of March 31, 2013:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	118,881	$	—	$	118,881
U.S. Treasury Bills	104,995		—		104,995
Commercial Paper	—		4,900		4,900
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	7,243		58,864		66,107
Commercial Paper	—		15,679		15,679
Corporate Bonds	—		34,795		34,795
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	22,904		32,454		55,358
Corporate Bonds	—		23,898		23,898
CDs	—		1,005		1,005
Other current assets:
Derivative assets	—		1,665		1,665
Total assets measured at fair value	$	254,023	$	173,260	$	427,283
Accrued liabilities:
Derivative liabilities	$	3	$	291	$	294

Fair Values as of March 31, 2012:

(in thousands)	Level 1		Level 2		Total
Cash and cash equivalents:
Cash	$	147,338	$	—	$	147,338
U.S. Treasury Bills	50,000		—		50,000
Commercial Paper	—		11,997		11,997
Short-term investments:
U.S. Treasury Bills and Government Agency Securities	12,898		48,998		61,896
Commercial Paper	—		20,039		20,039
Corporate Bonds	—		38,356		38,356
CDs	—		4,886		4,886
Long-term investments:
U.S. Treasury Bills and Government Agency Securities	6,647		23,190		29,837
Corporate Bonds	—		25,510		25,510
Other current assets:
Derivative assets	—		2,658		2,658
Total assets measured at fair value	$	216,883	$	175,634	$	392,517
Accrued liabilities:
Derivative liabilities	$	7	$	714	$	721